Hidden Instinct
by Macie F
Summary: This story will contain tcest, so be warned. Leonardo has feelings for a brother that he doesn't want. He thinks it's wrong and would never have given in, until said brother approached him.
1. Chapter 1

This is super short to begin with, but I wanted to get it started to help me stay motivated.

* * *

The door to his bedroom was thrown wide open. It bounced off the wall and closed itself once more, but a figure had managed to slip in quickly before that happened.

"Wha?" Leo slurred, shooting straight up in bed. Out of instinct he reached up for his katanas, only finding air. As the fog cleared from his abrupt awakening, he recognized his brothers figure. "Raph?" he squinted at him in the darkness. Raph stood stock still starring at Leo. His eyes slightly unfocused. "What's wrong?" Leo pushed himself farther up. His brother never had come to him at night before. Something must be wrong. When Raph took his first step forward, it hit him like a wall. The stench of alcohol rolled off his brother in waves. "You've been drinking," Leo acknowledged. Still not responding, Raph moved even close until he was standing next to Leo's bed. His mouth opened and closed a few times. It was as Leo made to swing his legs out of bed that Raph made his move. He flung himself on top of Leo and pressed their mouths together. Raph's mouth slid sloppily off of Leo's, thanks to the alcohol, and instead latched onto his neck.

Leo gasped at the sudden sensation. He couldn't think. Couldn't breathe. Couldn't move. Couldn't... The person he wanted for so long was sucking on his neck. No, not a person a turtle. Not just any turtle, his brother. He gave his head a shake. What was he doing? Nothing. He was doing nothing. Except he was. He was enjoying it. A churr was ripped from his body unwillingly as teeth bite down hard on his shoulder. "Enough!" Leo's brain screamed at him. Throwing his brother off of him usually could be a challenge, but since he was drunk it made it much easier. He flew to the other side of the bed as Leo rolled out from under him to stand. "What the hell," he gasped, trying to settle his breathing and hide his own arousal.

Raph ignored him, as he hung his head over the side and began puking.

"Seriously?" Leonardo grumbled.


	2. Chapter 2

He groaned as he rolled over. Wait? Rolled over. He wasn't in his hammock. Then where the hell was he? Slowly, he took in a deep breath. Leonardo. Oh, god. Why was he in his brother's room? His eyes were heavy as he opened them. The memories of last night were starting to come back. Raph was trying to work up the courage to tell his brother how he truly felt by drinking. He was only going to have one or two, which then led to three and four. Well you know how that ended... But he didn't remember how he ended up in here. Groaning again he tried to push himself up a little to look around.

"Here. Take these," Leo's hands appeared out of no where. He held out a glass of water and some pills.

Raph scowled as the sound cause his head to pound harder. Gratefully he took the pills though and muttered a thanks.

After Raph had placed the glass on the nightstand, Leo turned to leave. "Get some sleep, practice is cancelled," he said over his shoulder.

"Wait. Why am I in here?" Raph was praying that he hadn't done something stupid.

"Drunk you is too heavy to lug into your hammock," Leo paused at his doorway.

His mind was scrabbling to figure out what he had done last night, but was coming up empty still. "I didn't do anything to you, did I?"

Leonardo didn't meet his eyes. "Nothing I couldn't handle," he replied, before closing the door behind him.

Shit. So he had done something. Raph flopped his face back into a pillow. Leo hadn't seemed too upset though. Maybe he hadn't poured his heart out to him. Or maybe he had and Leo felt the same. But Leo wasn't looking directly at him when he'd answered the question. That couldn't be good, could it? His head hurt too much for this. Breathing deeply, he let Leo's scent fill him up as he drifted back to sleep.


	3. Chapter 3

Raph had had enough. He squared his shoulders and stomped to the dojo. Leonardo hasn't talked to him, let alone look at him since he woke up in his room yesterday. He wanted answers, and even more he wanted the weight off his shoulders from his secret. Leo was meditating in the center of the room. Raph shut the door as he said, "I need to talk to you."

Without opening his eyes, Leo responded, "What about?"

"The other night," Raph scrutinized his face, watching for any change that might give away what Leo was feeling.

"It's alright. You don't need to apologize for anything," Leo finally opened his eyes to meet his brother's.

"Leo, I need to tel-," but before he could finish, Leo had cut him off.

"No, forget it ever happened," Leo tried to smile at him and failed. He shifted uncomfortably on the floor.

"I have to-," Raph tried again.

"You're already forgiven," Leo quickly cut in.

"It's not-," he began.

"It's fine!" Leo broke and yelled in hope of keeping him quiet.

"Leo, shut up!" Raph roared. "I'm tryin' to say somethin'." His breathing was heavy as he tried to calm himself down. "I..," he started.

"Raph, no!" Leo begged.

"..love you, Leo," he finished, staring at Leo who had hung his head.

Silence hung between the two brothers. As the seconds ticked by, the hope Raph had was beginning to fade.

"I am your brother," Leo finally spoke. "Your leader. Do not forget that."

"I haven't," Raph took a step towards Leonardo, who finally looked up at him again.

"Whatever feelings are between us, you must forget them," his eyes harden.

"So you feel the same?" Raph's eyes widened.

"It does not matter!" Leo growled. "It is wrong!"

"It's not!" Raph was getting riled up again.

Leonardo jumped to his feet, "We're done here." He moved to walked passed Raph.

"No we ain't," Raph murmured as he grabbed ahold of Leo and pulled him close. Their second kiss wasn't as sloppy as the first. Raph's lips didn't slip off this time, instead they held firm against his brother's, waiting. Slowly, Raph began to move, sliding his tongue to brush against his brother's lips. He gently bit Leo's bottom lip and pulled back slightly. For a moment, a glorious moment, he felt Leo respond back and push back into him. That feeling was gone all to fast as he was pushed roughly to the ground. Leo stormed out of the dojo.


	4. Chapter 4

Over the next few days, Raph had tried to confront Leo again, but without success. Every time he managed to find Leonardo, he was always surrounded by other members of the family or else locked in his bedroom. Then there were the times where Raph couldn't find him at all. Damn ninja. Which is why Raph now found himself in this ridiculous position, hiding behind a pillar stalking his brother's door.

Leo had made a dash for the bathroom earlier from his safe haven and was quickly making his way back. Ducking inside, the door was an inch from latching as a large hand made contact and threw it back open. Leo stumbled as his brother barreled into the room.

"No more avoiding this," Raph said sternly, locking the door after he shut it.

"Raph, get out," Leonardo glared at him.

"No," he squared his shoulders.

"Get out!" Leo stepped towards him.

"No!" Raph towered over Leo.

Both brothers sized each other up, their breathing becoming heavy.

"You love me," Raphael reached up and brushed his fingers across Leo's cheek.

Leo turned his head to the side, his eyes turned down. "Don't," he murmured.

"And I love you," Raph's hand trailed down his arm.

"Stop. Saying. That," Leo ground out, his fists clenched.

"It's true," Raph took a step even closer.

"It's disgusting," he said, his head still hung.

"Don't you dare," Raph growled, grabbing onto Leo's face and holding it tight as he forced him to look up. "This is not disgusted," he spat. "What I feel for you could never be disgusting." He dipped his head so their lips were almost touching. "Tell me you don't want this," he leaned in and rested their foreheads together.

"Raph...," Leo whispered.

"I'll walk away right now and never mention it again," he continued.

"Raph," It came out louder this time. Leo's own hands reached up and grabbed ahold of Raph's waist.

"Say it," Raph urged him.

"I can't," he confessed.

"Exactly," he brought their lips together.

Leonardo melted into him. He pushed his worry and doubt away to be in this moment. Live in this moment. For once in his life to give into his desires and not focus on the expectations he's supposed to live up to. Raph's tongue ghosted across his bottom lip. He gladly opened up to give him access. Their tongues danced with one another while Leo's hands pulled Raph forward. When the back of his legs hit the edge of the bed, he made sure to bring Raph down with him as he fell into bliss.


	5. Chapter 5

As Raph fell on top of Leo, he managed to catch himself so as not to crush him. They had broken apart on their way down. Their eyes connected for a moment and Raph got a glimpse inside the fearless leader's walls. For once, Leonardo bared his soul, his wants and desires left out in the open. Raph was going to take full advantage, crushing back down onto the turtle beneath him.

Not wanting to waste time, Raph eagerly slipped his tongue passed his brother lips. Their tongues swirled together as Raph pressed his brother deeper into the mattress. His lower plastron ground against Leo's in a surprisingly pleasant sensation.

Wanting more, Raph pulled away. He gently nipped at Leo's bottom lip, pulling it as he went. "Scoot back," he rumbled.

Leo did as he was told and slide farther back onto the bed. His legs splayed wide to make room for Raphael.

Raph's tongue licked his lips before he moved towards his brother once more. He settled himself in the space Leo had created and gently began rubbing across the pouch that held Leo's penis. With his left hand busy, Raph pressed his other hand up to Leo's mouth. "Suck," he commanded, pressing a finger into the warm, wet mouth.

Again, Leo complied without a fight, taking the finger as deep as he could and sucking hard. Raph pushed his finger in and out and dipped his other finger inside his brother's slit to brush across the head of his penis. Leonardo groaned, his cock expanding even more from the extra attention.

"Yeah, you like that Leo," Raph hummed. His own erection growing at the sight of his brother. "Get that finger nice and wet for me." He moved his other hand down to play with Leo's tail.

Leo whimpered at first from the loss of contact until the hand wrapped around his other appendage, pulling and twisting. His toes curled and hips rose slightly off the bed. He couldn't contain the churr that this new addition brought forth.

With a wet pop, Raph pulled his finger from Leo's working mouth. Satisfied, he circled around Leo's puckering hole using the saliva as lubricant. He pushed into the tight ring without warning.

Leo gasped, "Raph." His head slammed back.

"Tell me what you want," he said, as he continued to work his finger along the tight, virgin passageway. After tracing around the entire hole, he pulled his finger almost all the way out waiting for Leonardo's response.

"You know," Leo moaned. No longer able to stand the pressure between his legs, his cock slipped free.

Raphael rewarded him by ramming his finger back in his ass.

"Nuhh.. mmm," Leo arched upwards at the sudden intrusion.

Raph picked up a rhythm of pushing in quickly and slowly drawing back out. "You have to say it," he pinched the tip of Leo's tail.

Gasping again, Leo shook. His body was dancing the fine line between pain and pleasure. "I want.. ahhh," his eyes rolled back into his head.

Raph had again surprised him by taking his full length into his mouth. His head bobbed up and down as his tongue dragged along the underside. Swiping his tongue across the slit at the head, he pulled back to chuckle, "I didn't quite catch that."

Leo pushed himself up to glare at his brother. "I need you."

The smile wiped off of Raphael's face. "Good," he turned serious. "Lay back down."

Leonardo barely was flat again when he felt something much larger pressing into his ass. He hissed as his hole was breached.

"Easy bro," Raph purred, nuzzling the side of his face. "Relax," he moved down to suck at Leo's neck. Dipping between them, he took ahold of his penis as well to give him some pleasure with the pain. Thinking it may be best to get it over with, Raph gave one big thrust and buried himself to the hilt.

"Ahhhh..," Leo cried out.

"Sorry," Raph kissed his way back up to Leo's lips. Claiming them, he pumped him brother's softening dick. "You okay?" he pulled away.

"Keep going," Leo breathed.

Careful this time, Raph pulled out to the tip and pushed back in. He still jerked away at the cock in his grasp as he moved in and out. When his brother's ass loosened up a little, Raphael picked up the pace. He dropped Leo's dick in order to grasp onto his side and tilt his ass up in the air for better access.

This new angle drove Raph's dick straight into Leo's prostate causing him to cry out for a third time. The room quickly filled with churrs and moans from the pair.

"Faster," Leo urged, squirming beneath the larger turtle. His dick bulging painfully, seeking release.

Raph's eyes clouded over and his instincts took control. He pounded into the willing ass mercilessly.

One more direct hit to his prostate sent Leonardo cascading over the edge. His load splashing on both their plastrons. The muscles in Leo's ass clenched with his release. The extra friction caused Raph to tumble into ecstasy with him. The inside of him was coated with his brother's sperm.

Panting, Raph collapsed where he was. When both turtles had come down from their high, Raph pulled his dick out and rolled to the side. He snuggled against Leo and drifted off without another word.

Cum oozed from Leo's stretched hole, puddling on the sheet. With his hormones returning to normal, the impact of what they just did together settled upon him. He starred at the ceiling listening to his brother's soft snores next to him. Tomorrow he would have to deal with another weight on his shoulders, guilt.


	6. Chapter 6

_What have I done? What have I done?_

That thought taunted Leonardo since the moment he woke up laying next to his brother _._ He ran from the room and emptied his stomach into the toilet.

 _He's your brother. He's your brother._

He'd been in the shower scrubbing himself raw for who knows how long _._ The feeling of his brother's touch wouldn't leave him no matter how hard he rubbed _._ Hot water scalded his skin. Leonardo hoped it would wash away his sin.

The door to the bathroom opened causing him to jump. Leo quickly shut off the water. Before he had a chance to leave, Raphael pulled back the shower curtain.

"There you are," he smiled.

"I was just finishing," Leo managed a small smile in return, but couldn't quiet meet his eyes.

"Come here," Raphael pulled him in for a kiss _._

Leonardo allowed it for a second before pulling back, "The others will be awake soon."

"Alright, alright," Raph rested their foreheads together.

Leo moved to grab a towel. "I'll see you at practice."

Raphael reached out and took hold of his arm. "Hey. You okay?" he asked, concerned.

"Of course," Leo smiled slightly again.

 _What will the others say?_

Leo tried not to let his distress show during practice. His katas weren't as sharp as usual, but Mikey managed to draw most of the attention to himself by almost falling asleep on his feet. He was very thankful he wasn't sparring against Raph today. Donatello almost put him down and out once, which Sensei noticed. Instead of berating Leonardo, however, he praised Donnie for his effort.

 _I have to stop. I have to be stopped._

At breakfast, he only made comments when he had to. His mind whirled. He would never be able to tell Raphael no. Not since they had sex. It felt too good. Too wrong. No, there had to be another answer. He could tell Sensei who would forbid it. But that would mean admitting to his weakness. The shame he would fill would be too much. Maybe he could leave for awhile and then return once he was normal again? Would he ever be normal again _?_ Or would these thoughts haunt him forever?

 _You know what you must do._

Raphael had approached him later in the day. "I wanna be with you again tonight," he had whispered.

"No. We can't be together all the time. The others might notice," Leo said as an excuse.

 _It has to be done._

Leonardo bid the others good night and retired to his room. He had read about a practice that samurai used before. Kneeling in the center of his room, he removed his katanas and laid them carefully to the side. The act itself would have to be modified slightly given his mutation. Pulling out a short knife, he rested it against his neck. His plastron would have been to hard to cut through on his own. Taking a deep breath, he closed his eyes and drew the knife across his throat.


End file.
